SIMPLE STEREO TRANSMISSION SYSTEM

PROBLEM TO BE SOLVED: To configure a stereo echo canceller with a few number of ADFs(adaptive digital filters) by allowing a transmitter side to integrate N-sets of microphone inputs into one and sending sub information denoting a selected microphone so as to allow a receiver side to generate a stereophonic sense and to localize a sound image. SOLUTION: A transmission voice of a talker A is picked up by two microphones 1, 2 and transduced into an electric signal, an adder 5 sums the signals to be transmission main information M(t), and on the other hand, a level detector 6 decides it that the microphone 1 is in use and outputs sub information S(t). The transmitted information is given to a decoder 9, where transmission main information M(t) and sub information S(t) are separated and decoded, a speaker 15 is driven and the sound image of the sender A is localized at the position. In this case, since only an output speaker 15 is in use, an ADF 100 generates an echo replical similarly to the case with a monaural echo canceller and an ADF 200 outputs nothing.